为合理量化地铁盾构隧道建设的碳排放水平并测度其减排潜力，采用LCA方法开展地铁盾构隧道建设阶段碳排放评价工作，并结合实际工程数据进行碳排放强度和水平量化分析； 同时，基于情景分析法从推广绿色建材及清洁能源等角度探究其减碳潜力。研究结果表明： 单环预制管片碳排放强度约为7.1 tCO2e/环，而单位地铁盾构隧道建设碳排放强度约为1.1万tCO2e/km； 其中，建材及预制管片生产、运输及盾构施工和安装等过程占比分别为72.7%、1.9%和25.4%。若通过提高再生建材和优化能源结构，年均碳排放量下降约6%，但碳排放量累积可达约13 MtCO2e（2022—2035年），与2020年全国城市轨道交通运营排放基本持平。

To reasonably quantify the carbonemissions level of constructing a metro shield tunnel and measure its emission reduction potential, the lifecycle assessment method is adopted to evaluate the carbon emissions during the construction of a metro shield tunnel and quantitatively analyze the intensity and level of carbon emissions based on actual engineering data. Thereafter, based on the scenario analysis method, the carbon reduction potential is explored from the perspective of promoting green building materials and clean new energy. The research results reveal that the carbon emission intensity of a singlering prefabricated segment is ~7.1 tCO2e/ring, whereas that of constructing a unit of metro shield tunnel is ~1.1×104 tCO2e/km. The carbon emission intensities of the material and prefabricated segmentprocessing phase, transportation phase, and shield tunneling and segment installation phase respectively account for 72.7%, 1.9%, and 25.4% of the total emissions of the entire construction. Although further utilization of recycled building materials and improvement of the clean energy structure can reduce the average annual carbon emissions by~6%, the cumulative carbon emissions from 2022 to 2035 will add up to ~1.3×107 t CO2e, which is equivalent to the national metro operation emissions in 2020.